Infant reactivity to redundant proprioceptive and auditory stimulation

Leland D. Van den Daele

The role of genetic factors in infant response to redundancy was evaluated through observation of the behavior of three sets of same-sex fraternal twins and six sets of same-sex identical twins to combinations of redundant proprioceptive and auditory stimulation. The twins ranged in age from 6 weeks to 24 weeks. One member of each twin set was placed on each side of a partition in a motor-driven rockerbox, and four 1-minute treatments were administered in mixed order, with 1-minute pre-treatment and post-treatment periods. The treatments consisted of combinations of fast and slow rocking under conditions of sound and no sound. An observer rated the activity level of each twin on a 5-point scale at 30-second intervals. Treatment was associated with a significant decline of infant activity independent of zygosity. Identical twins exhibited marked behavioral consistency compared to...